The present invention is directed to implants, and more particularly to trial implants that are durable and easy to manipulate.
Orthopedic procedures generally involve the resection of a bone, a trialing step to determine the proper size of a permanent implant, and implantation of the permanent implant. For instance, it has long been known in the art for orthopedic procedures involving the knee to include the resection of one or both tibial condyles, or portions thereof. The resection itself generally entails cutting and removing at least a portion of the proximal end of a tibial condyle and replacing same with a permanent tibial implant, which is typically comprised of a base plate and an insert. This type of knee surgery may be necessitated by a fracture or other deterioration of the tibial bone (as well as corresponding femoral bone). As such, the permanent tibial implant is used to improve or restore the normal functionality of the knee joint.
During the surgical procedure, a surgeon will resect an appropriately sized portion of the proximal tibial condyle to prepare the tibial platform. Often, a cut is made at a specific depth in the distal direction. The resected surface is then prepared to receive the permanent implant typically including both a metal baseplate and a polymeric insert, although certain permanent implants are constructed entirely of either metal or a polymeric material. However, as the size of the patient, the tibial bone, and the resected area can vary greatly from procedure to procedure, the particular size and shape of the permanent implant varies as well. It can often be difficult to determine the exact size and orientation of the permanent tibial implant prior to actually performing the surgical procedure.
In order to more accurately and precisely fit the permanent tibial implant to the resected bone, surgeons may use a set of trial implants which can be inserted and removed during the procedure to determine which provides the best fit according to the resected bone surface. The implant's height, size, orientation, and cooperation with a corresponding femoral bone or implant are some of the many factors taken into consideration when fitting a patient with an implant so as to properly balance the knee and restore same to its original capacity.
Existing trial implants are generally comprised entirely of a polymer or a similar material, so as to save in manufacturing costs. As a surgical tool is often used to attach to and manipulate each insert, the polymeric material of the insert can be easily damaged during the trialing procedure. This can lead to portions of the polymeric material being inadvertently introduced into the body of the patient. Moreover, because sets of trial implants can be reused, individual inserts are often damaged to a point where they are no longer functional and must be replaced before future surgeries can be conducted. It is also common that a set of trial implants is designed to require a dedicated instrument to connect with the inserts. The replacement of certain inserts and the acquisition of a dedicated instrument make these existing sets costly.
Another drawback with existing trial implants is that a surgical tool must attach to the implants on their exterior surfaces, and often times their bearing surfaces. This leads to contact between the surgical tool and the anatomy surrounding the implantation site that may be unintentional, but is often unavoidable. Such contact can cause damage to the surrounding bone and tissue, and furthermore, may hinder a surgeon's ability to adequately position the implant.
Thus, a need exists for a set of one or more trial implants that are more durable and hold up better to repeated use, while at the same time keeping costs associated with manufacturing of same low. A need also exists for a set of one or more trial implants that cooperate with a general or specialized surgical tool such that contact between the tool and the anatomy of the patient is substantially or wholly eliminated.